Proliferation Rate Ki-67 Research Articles

Prognostic Significance of C-MYC and EGFR Overexpression in Gastrointestinal Stromal Tumors: An Immunohistochemical Study

Introduction: In addition to mutations in KIT and PDGFRA, many other genetic alterations have been described in gastrointestinal stromal tumors (GISTs), including amplifications of C-MYC and EGFR, which are often associated with increased protein expression. The main of this study was to investigate the prognostic significance of C-MYC and EGFR expression in GISTs using immunohistochemistry (IHC). Methods: We collected all GIST cases over a 16-year period. These cases were tested using antibodies against C-MYC (Leica, clone EP121) and EGFR (Leica, clone 113). C-MYC staining was assessed using the H-score method for nuclear, cytoplasmic, and combined staining. For EGFR staining (either cytoplasmic or nuclear), the intensity was graded as follows: 0 (no staining), 1 (weak staining), 2 (moderate staining), and 3 (strong staining). The percentage of positive cells was evaluated using a semiquantitative approach. Statistical analysis was performed using SPSS24. Results: A total of 37 cases were included in our study. Nuclear expression of C-MYC was observed in 43% of the cases, with a high H-score in 43%. A statistically significant association was found between a high nuclear H-score for C-MYC and mitotic rate (P=0.046), as well as a high Ki-67 proliferation rate (P=0.046). However, no statistically significant associations were identified between the nuclear H-score of C-MYC and other clinical, pathologic, or survival data. Cytoplasmic expression of C-MYC was noted in 22% of cases, but no significant correlations were found with the clinicopathological data. EGFR staining was observed in 86% of cases, with a high score of 51%. EGFR expression was significantly associated with the mitotic index (P=0.012) and Ki-67 proliferation rate (P=0.046). Conclusions: Our findings suggest that both C-MYC and EGFR may be overexpressed and/or amplified in GISTs, indicating their potential prognostic role. This could also pave the way for therapeutic strategies targeting these proteins.

A Diagnostic Challenge in the Biopsy of a Mammographic Abnormality

Abstract Introduction/Objective Primary breast marginal zone lymphoma (MZL) is an uncommon subtype of extranodal lymphoma, and its diagnosis presents challenges, particularly in distinguishing it from lymphoplasmacytic lymphoma (LPL). MYD88 L265P mutation has been identified in a subset of marginal zone lymphomas, comprising 6-9% of cases. This genetic alteration further complicates the differentiation between MZL and LPL in breast tumors. We present a case highlighting the diagnostic complexities associated with primary breast MZL. Methods/Case Report A 71-year-old female patient underwent mammographic screening, which revealed a suspicious lesion in her left breast. Subsequent PET scan showed a hypermetabolic area consistent with a primary breast lesion. Biopsy histology exhibited a diffuse atypical lymphoid infiltration with varying proportions of neoplastic lymphocytes. Immunohistochemical analysis revealed positivity for CD20, PAX5, BCL2, CD138, MUM1, and negativity for CD3, CD5, Cyclin D1, CD10, CD23, CD34, BCL6, TDT, CD30, GATA3, and CK AE1/3. Additionally, there was lambda light chain restriction, and the Ki67 proliferation rate index was approximately 50%. Fish analysis indicated abnormal BCL6 gene rearrangement. Molecular genetic testing confirmed the presence of MYD88 mutation with c.794T>C p.L265P. Notably, bone marrow biopsy showed no abnormalities, with normal hematopoiesis. Serum electrophoresis and immunofixation detected an IgM monoclonal protein with lambda light chain specificity. Results (if a Case Study enter NA) NA Conclusion The diagnosis of primary breast MZL was favored over LPL due to the absence of common LPL- associated symptoms such as bone marrow involvement. However, the distinction between these entities remains challenging, underscoring the importance of comprehensive diagnostic approaches integrating histopathology, immunohistochemistry, and molecular genetics. Further research is warranted to enhance diagnostic certainty in such cases, particularly as the management of MZL and LPL becomes increasingly specific with the advent of novel therapeutic agents and ongoing clinical trials.

Association of clinicopathologic and sonographic features with stromal tumor-infiltrating lymphocytes in triple-negative breast cancer

BackgroundIncreased level of stromal tumor-infiltrating lymphocytes (sTILs) are associated with therapeutic outcomes and prognosis in triple-negative breast cancer (TNBC). This study aimed to investigate the associations of clinicopathologic and sonographic features with sTILs level in TNBC.MethodsThis study included invasive TNBC patients with postoperative evaluation of sTILs after surgical resection. Tumor shape, margin, orientation, echo pattern, posterior features, calcification, and vascularity were retrospectively evaluated. The patients were categorized into high-sTILs (≥ 20%) and low-sTILs (< 20%) level groups. Chi-square or Fisher’s exact tests were used to assess the association of clinicopathologic and sonographic features with sTILs level.ResultsThe 171 patients (mean ± SD age, 54.7 ± 10.3 years [range, 22‒87 years]) included 58.5% (100/171) with low-sTILs level and 41.5% (71/171) with high-sTILs level. The TNBC tumors with high-sTILs level were more likely to be no special type invasive carcinoma (p = 0.008), higher histologic grade (p = 0.029), higher Ki-67 proliferation rate (all p < 0.05), and lower frequency of associated DCIS component (p = 0.026). In addition, the TNBC tumors with high-sTILs level were more likely to be an oval or round shape (p = 0.001), parallel orientation (p = 0.011), circumscribed or micro-lobulated margins (p < 0.001), complex cystic and solid echo patterns (p = 0.001), posterior enhancement (p = 0.002), and less likely to have a heterogeneous pattern (p = 0.001) and no posterior features (p = 0.002).ConclusionsThis preliminary study showed that preoperative sonographic characteristics could be helpful in distinguishing high-sTILs from low-sTILs in TNBC patients.

Abstract 4771: Assessment of Ki67 proliferation index in pre-malignant colonic adenomas: Implication for new biomarker testing to predict metachronous disease (The INCISE project)

Abstract Approximately 40% of patients are found to have polyps at bowel screening colonoscopy, which are associated with a higher risk of developing future polyps or colorectal cancer. The British Society of Gastroenterology 2020 (BSG20) guidelines stratify patients into high/low risk of metachronous disease, using the size, dysplasia, and number of polyps found at index colonoscopy. This study aims to explore the prognostic significance of Ki67 proliferation percentages in adenomatous polyps, with metachronous disease. Tissue microarray (TMA) was constructed from 1201 index adenomatous polyps with representative cores of basal and luminal adenomatous epithelia. 67% patients were identified as high risk at index colonoscopy. The median time to detect metachronous polyps was 55 months (range 6-72 months) with 56% of patients developing metachronous polyps by the end of follow-up. TMA was stained for Ki67 using immunohistochemistry. Ki67 proliferation percentages in adenomatous epithelia was quantified using QuPath. Data was split into training (n=830) and test (n=371) datasets. The Ki67 proliferation cutpoint was made using Survmine R package using the training dataset. X2 test was used to study associations with clinicopathological criteria and Kaplan survival analysis was used to assess Ki67 association with metachronous lesions. Ki67 percentages were higher in lumina than in basal adenomatous epithelium (median Ki67 were 63% &amp; 48%; respectively). Total Ki67 percentages were computed by averaging luminal and basal values. Thresholds of 70%, 64% and 59% were employed to classify patients into low/high categories based on luminal, basal or total percentages; respectively. In the training cohort, high luminal, basal or total Ki67 were associated with metachronous lesions (p values 0.032, &amp;lt;0.001 and 0.006; respectively). Other associations were significant between luminal or total Ki67 and location of index polyps (p=0.017 &amp; p=0.044; respectively), histology (p=0.019) and advanced future lesion status (p=0.002 &amp; p&amp;lt;0.001; respectively). In multivariate cox regression analysis, high Ki67 was an independent prognostic factor for metachronous polyps (luminal Ki67 HR=1.28, CI: 1.052-1.560, p=0.014; basal Ki67 HR=1.639, CI: 1.313-2.046, p&amp;lt;0.001; total Ki67 HR=1.344, CI: 1.105-1.635, p=0.003) when adjusted to number of index polyps and BSG20 risk score. BSG20 risk score stratification of patients in terms of metachronous disease was improved when combined with luminal, basal or total Ki67 in the training datasets (all p&amp;lt;0.05). Prediction of metachronous disease by the combined groups was validated in the test cohort for luminal, basal and total Ki67 (all p&amp;lt;0.05). High Ki67 proliferation rates in adenomatous polyps are independently associated with the development of metachronous polyps and may help improve the BSG20 criteria. Citation Format: Gerard P. Lynch, Aula Ammar, Christopher Bigley, Mark Johnstone, Jakub Jawny, Hannah Morgan, Jennifer Hay, Noori Maka, Stephen McSorley, Joanne Edwards. Assessment of Ki67 proliferation index in pre-malignant colonic adenomas: Implication for new biomarker testing to predict metachronous disease (The INCISE project) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4771.

TP53 mutation is frequent in mantle cell lymphoma with EZH2 expression and have dismal outcome when both are present

Enhancer of zeste homolog 2 (EZH2) expression is found in about 40% of mantle cell lymphoma (MCL) patients, which is associated with aggressive histology, high Ki-67 proliferation rate, p53 mutant pattern and inferior overall survival (OS). We conducted 11-gene (ATM, BIRC3, CCND1, KMT2C, KMT2D, NOTCH1, NOTCH2, RB1, TP53, TRAF2 and UBR5) next generation sequencing panel to shed more light on MCL with EZH2 expression (EZH2+ MCL). EZH2+ MCL more frequently harbor TP53 mutation compared to EZH2(−) MCL (41.2% vs. 19.1%, respectively, p = 0.045). TP53 mutation and EZH2 expression demonstrated overlapping features including aggressive histology, high Ki-67 proliferation rate and p53 mutant pattern by immunohistochemistry. Comparative analysis disclosed that EZH2 expression correlates with high Ki-67 proliferation rate irrespective of TP53 mutation. Aggressive histology is associated with EZH2 expression or TP53 mutation, possibly via independent mechanisms. p53 mutant pattern is due to TP53 mutation. MCL patients with EZH2 expression or TP53 mutation show inferior outcome and when both are present, patients have dismal outcome.

Fibrin-associated large B-cell lymphoma arising in an endovascular graft: first case report in Korea.

Fibrin-associated large B-cell lymphoma (FA-LBCL) is an extremely rare subtype of LBCL that consists of microscopic aggregates of atypical large B cells in the background of fibrin. Here, we report the first case of FA-LBCL in Korea. A 57-year-old male presented with a large amount of thrombus in the thoracic aorta during follow-up for graft replacement of the thoracoabdominal aorta 8 years prior. The removed thrombus, measuring 4.3 × 3.1 cm, histologically exhibited eosinophilic fibrinous material with several small clusters of atypical lymphoid cells at the periphery. The atypical cells were positive for CD20 by immunohistochemistry and for Epstein-Barr virus by in situ hybridization. The Ki-67 proliferation rate was 85%. The patient was still alive with no recurrence at the 7-year follow-up after thrombectomy. Although the diagnosis can be very difficult and challenging due to its paucicellular features, pathologists should be aware of FALBCL, which has likely been underestimated in routine evaluations of thrombi.

Intratumoral heterogeneity of Ki67 proliferation index outperforms conventional immunohistochemistry prognostic factors in estrogen receptor-positive HER2-negative breast cancer.

In breast cancer (BC), pathologists visually score ER, PR, HER2, and Ki67 biomarkers to assess tumor properties and predict patient outcomes. This does not systematically account for intratumoral heterogeneity (ITH) which has been reported to provide prognostic value. This study utilized digital image analysis (DIA) and computational pathology methods to investigate the prognostic value of ITH indicators in ER-positive (ER+) HER2-negative (HER2-) BC patients. Whole slide images (WSIs) of surgically excised specimens stained for ER, PR, Ki67, and HER2 from 254 patients were used. DIA with tumor tissue segmentation and detection of biomarker-positive cells was performed. The DIA-generated data were subsampled by a hexagonal grid to compute Haralick's texture indicators for ER, PR, and Ki67. Cox regression analyses were performed to assess the prognostic significance of the immunohistochemistry (IHC) and ITH indicators in the context of clinicopathologic variables. In multivariable analysis, the ITH of Ki67-positive cells, measured by Haralick's texture entropy, emerged as an independent predictor of worse BC-specific survival (BCSS) (hazard ratio (HR) = 2.64, p-value = 0.0049), along with lymph node involvement (HR = 2.26, p-value = 0.0195). Remarkably, the entropy representing the spatial disarrangement of tumor proliferation outperformed the proliferation rate per se established either by pathology reports or DIA. We conclude that the Ki67 entropy indicator enables a more comprehensive risk assessment with regard to BCSS, especially in cases with borderline Ki67 proliferation rates. The study further demonstrates the benefits of high-capacity DIA-generated data for quantifying the essentially subvisual ITH properties.

Grading medullary thyroid carcinoma on fine-needle aspiration cytology specimens with the International Medullary Thyroid Carcinoma Grading System: Acytologic-histologic correlation.

Medullary thyroid carcinoma (MTC) is a rare cancer of parafollicular C-cell origin. The International MTC Grading System (IMTCGS) incorporates mitotic activity, the presence of necrosis, and the Ki67 proliferation rate (PR) to classify MTCs as low or high grade. The ability to predict IMTCGS grade in cytology was assessed. MTCs with cytology and subsequent surgical follow-up were reviewed. Cytology slides were reviewed for mitotic figures, apoptoses, and necrosis, and a Ki67 PR was calculated when possible. Findings were correlated with final IMTCGS grade. Twenty-five MTC fine-needle aspirations (FNAs) were identified, with nine identified as high grade (36%). By using a PR cutoff of 5%, Ki67 on FNA material (Ki67FNA) showed 92% concordance (n=22 of 24) with surgical Ki67 and a correlation coefficient (R2) of 0.72. Sensitivity and specificity of Ki67FNA for predicting high-grade MTC were 38% and 100%, respectively. Multiple mitotic figures were present in a single slide of 43% (n=3 of 7) of evaluable high-grade MTCs, whereas only one of 16 low-grade MTCs showed a single mitotic figure. Definitive apoptoses were present in five of seven high-grade MTC FNAs but were absent in 16 low-grade MTCs. The sensitivity and specificity of apoptoses/necrosis on cytology for high-grade MTCs were 71% and 88%, respectively. Ki67FNA ≥5% shows low sensitivity but high specificity for predicting high-grade MTC. The presence of multiple mitotic figures in a single slide or definitive apoptotic bodies are both highly suggestive of high-grade MTC, and should warrant a close examination for necrosis and a careful Ki67 PR count.

First Report of Asymptomatic Solitary High-Grade B-Cell Lymphoma NOS: An Enigmatic Entity

Background High-grade B cell lymphoma (HGBL) is a new disease entity introduced by WHO in 2016, including two types: HGBL with a double hit (DH) or triple hit (TH) and HGBL, not otherwise specified (NOS). HGBL DH/TH are defined by genetic rearrangements of specific oncogenes MYC, BCL2 and/or BCL6, while HGBL NOS is defined purely base on morphology in the absence of these genes. HGBL DH/TH is known for its poor prognostication given its propensity to rapidly progress and disseminate, however HGBL NOS remains ill-defined and poorly understood with no tangible literature describing its clinical nature and therapeutic susceptibility. Case presentation A 76-year-old post-menopausal woman with no significant PMH presented for evaluation of painless hematuria during a routine office visit. Evaluation with imaging showed a suspicious incidental liver mass concerning for possible metastatic or primary liver cancer. Obtained labs were unremarkable, including serum LDH, serological testing for hepatitis B/C and HIV1/2, and typical tumor markers. PET scan showed focal uptake of tracer in liver with no nodal involvement. Liver biopsy revealed diffuse infiltration by atypical lymphocytes. Immunohistochemical analysis showed CD20 and CD10 positivity, negative CD30, and high Ki-67 proliferation rate of 100%, however the absence of MYC, BCL6, BCL2, and t(8;14) rearrangements on FISH ruled out Burkitt and DH/TH lymphoma, consistent with HGBL-NOS. Following discussions with Henry Ford Lymphoma Tumor Board, patient was treated with six cycles of R-CHOP, where follow-up imaging indicated remission of her lymphoma. Conclusion This represents an extraordinary first report of HGBL NOS manifesting as an isolated primary hepatic lymphoma in the complete absence of clinical symptoms. The significance of this case lies in its atypical extra-nodal site of involvement and total absence of clinical symptoms and serological markers, underscoring the unfulfilled need to further describe this enigmatic entity.

Occupational exposure to pesticides dysregulates systemic Th1/Th2/Th17 cytokines and correlates with poor clinical outcomes in breast cancer patients

Pesticides are compounds known to cause immunetoxicity in exposed individuals, which have a potential to substantially modify the prognosis of pathologies dependent on an efficient immune response, such as breast cancer. In this context, we examined the circulating cytokine profile of Th1/Th2/Th17 patterns in women occupationally exposed to pesticides and their correlation with worse prognostic outcomes. Peripheral blood samples were collected from 187 rural working women with breast cancer, occupationally exposed or not to pesticides, to quantify the levels of cytokines IL-1β, IL-12, IL-4, IL-17-A, and TNF -α. Data on the disease profile and clinical outcomes were collected through medical follow-up. IL-12 was reduced in exposed women with tumors larger than 2 cm and in those with lymph node metastases. Significantly reduced levels of IL-17A were observed in exposed patients with Luminal B subtype tumors, with high ki67 proliferation rates, high histological grade, and positive for the progesterone receptor. Reduced IL-4 was also seen in exposed women with lymph node invasion. Our data show that occupational exposure to pesticides induces significant changes in the levels of cytokines necessary for tumor control and correlates with poor prognosis clinical outcomes in breast cancer.

THU094 Multiple Endocrine Neoplasia Type 1 Tumor Recurrence After Loss To Follow Up

Abstract Disclosure: S.J. Sternlieb: None. K.G. Romo: None. R.S. Boothe: None. D. Englert: None. N. Manuel: None. Q.Z. Iqbal: None. Multiple Endocrine Neoplasia Type 1 Tumor Recurrence After Loss to Follow-up Sternlieb, S. J., Romo, K.G., Boothe, R., Manuel, N., Iqbal, Q.Z., Grissett, B., Englert, D. Background: MEN1 is a rare, autosomal dominant tumor disorder due to mutations in the MEN1 tumor suppressor gene. It is characterized by parathyroid, enteropancreatic and pituitary tumors. We present a young woman with MEN1 with prolactinoma, primary hyperparathyroidism and multiple pancreatic neuroendocrine tumors. Clinical Case: A 30-year-old woman with MEN1 presented with complaints of abdominal pain and GI bleeding (GIB). She was diagnosed with a prolactinoma at age 14 after presenting for primary amenorrhea and galactorrhea. She didn’t tolerate medical therapy with bromocriptine or cabergoline and required transphenoidal resection. At age 19, she presented with hypoglycemia and was found to have multiple pancreatic neuroendocrine tumors (NET) as well as a left (L) adrenal gland tumor. She underwent distal pancreatectomy and L adrenalectomy. Ten tumors in the pancreas stained variably for insulin, glucagon, gastrin and VIP. Multiple cortical adenomas were found in the adrenal gland. Post-operatively she developed a spinal cord hematoma related to placement of an epidural catheter for pain control, which led to permanent paraplegia. At age 21, she was diagnosed with primary hyperparathyroidism. She underwent left parathyroidectomy, then was lost to follow-up for 9 years. EGD showed multiple superficial duodenal ulcers. MRI brain identified a right (R) cavernous sinus mass inseparable from the R pituitary. CT abdomen showed a pancreatic head mass. Given the concern for neuroendocrine etiology, she underwent an EUS showing a pancreatic mass and a liver mass. Pancreatic mass pathology confirmed low-grade NET with Ki67 proliferation rate &amp;lt;1%, positive synaptophysin and chromogranin staining. After multidisciplinary discussion, the consensus was to continue PPI and sucralfate for GI ulcers, start lanreotide, and obtain somatostatin receptor scintigraphy. Surgery was not recommended unless significant GIB occurred on maximal therapy. She was referred to follow-up with GI, endocrinology, and NSGY. Since discharge, she has presented several times to other hospitals for abdominal pain, but has not adhered to follow-up. Conclusions: This case of recurrent neuroendocrine and pituitary tumors despite prior resections demonstrates the consequences of prolonged loss to follow-up with MEN1. Without routine surveillance, recurrence is likely. This patient lives in a rural area with lack of access to nearby subspecialty care, which is a barrier. More resources are needed to support patients with social barriers and progressive endocrinopathies. Key words: MEN1, prolactinoma, gastrinoma, NET, health care barriers Presentation: Thursday, June 15, 2023

OS13.5.A MOLECULAR CHARACTERISTICS AND PROGNOSTIC BIOMARKERS OF CENTRAL NEUROCYTOMA

Abstract BACKGROUND Central neurocytomas (CN) are intraventricular brain tumors predominantly arising in young adults. Long-term prognosis is favorable in the majority of cases, whereas a considerable proportion of patients experience disease progression. Progression risk is currently assessed morphologically based on the presence of histological signs of atypia and/or an elevated ki67 proliferation index (&amp;gt;3%). The molecular profile and etiology of CN remains elusive and molecular biomarkers for risk stratification have not been identified yet. MATERIAL AND METHODS We analyzed a retrospective multi-institutional cohort of 108 CNs by genome-wide DNA methylation profiling. DNA whole exome sequencing was performed in 12 cases. Follow-up information was available for 45 patients. RESULTS The histological diagnosis of neurocytoma was epigenetically confirmed in 96 cases. 12/108 cases (11%) were assigned to another methylation class based on the v12.5 Heidelberg Brain Tumor Classifier. Median age at diagnosis was 29 years, distribution among sexes was equal. Based on morphology and immunohistochemistry, tumors were diagnosed as classical CN (n = 71), CN with increased proliferation (n = 10) and atypical CN (n = 15). In 49/72 cases (68%, NA=24), an elevated Ki67 above 3% was reported. DNA whole exome sequencing revealed no recurrent genetic alterations. Most copy number profiles were balanced (n = 87), while some cases (n = 9) showed individual chromosomal alterations (e.g. chr. +5, n = 3). Tumor recurrence was observed in 16/45 (36%, NA = 51) of cases. Median progression-free survival (PFS) after the initial diagnosis was 72 months, none of the patients died (observation time: range 3 - 141 months). In 16 cases, surgery was followed by adjuvant radiotherapy, predominantly in patients with subtotal resection (STR: n = 11, 69%; GTR: n = 5). There was no significantly different outcome between classical and atypical CNs (n = 45; median PFS 73 months vs. 26 months, p-value = 0.067) and cases with low vs. elevated Ki67 (n = 45; median PFS NA vs. 72 months, p-value = 0.44). CONCLUSION Preliminary data of our study indicate that histological diagnosis and Ki67 proliferation rate were not associated with PFS in epigenetically defined neurocytomas. Further research using clinical and molecular covariates is necessary to identify novel biomarkers to predict recurrence risk and benefit from adjuvant radiotherapy.

Histomorphometric Analysis of 38 Giant Cell Tumors of Bone after Recurrence as Compared to Changes Following Denosumab Treatment.

Giant cell tumor of bone (GCTB) is an osteolytic tumor driven by an H3F3A-mutated mononuclear cell with the accumulation of osteoclastic giant cells. We analyzed tissue from 13 patients with recurrence and 25 patients with denosumab therapy, including two cases of malignant transformation. We found a decrease in the total number of cells (p = 0.03), but not in the individual cell populations when comparing primary and recurrence. The patients treated with denosumab showed induction of osteoid formation increasing during therapy. The total number of cells was reduced (p < 0.0001) and the number of H3F3A-mutated tumor cells decreased (p = 0.0001), while the H3F3A wild-type population remained stable. The KI-67 proliferation rate dropped from 10% to 1% and Runx2- and SATB2-positive cells were reduced. The two cases of malignant transformation revealed a loss of the H3F3A-mutated cells, while the KI-67 rate increased. Changes in RUNX2 and SATB2 expression were higher in one sarcoma, while in the other RUNX2 was decreased and SATB2-positive cells were completely lost. We conclude that denosumab has a strong impact on the morphology of GCTB. KI-67, RUNX2 and SATB2 expression differed depending on the benign or malignant course of the tumor under denosumab therapy.

Blastoid and Pleomorphic Mantle Cell Lymphoma Demonstrate Distinct Clinicopathologic and Genetic Features.

The blastoid (B) and pleomorphic (P) variants of mantle cell lymphoma (MCL) are associated with aggressive clinical behavior. In this study, we collected 102 cases of B-MCL and P-MCL from untreated patients. We reviewed clinical data, analyzed morphologic features using an image analysis tool (ImageJ) and we assessed mutational and gene expression profiles. The chromatin pattern of lymphoma cells was assessed quantitatively by the pixel value. Cases of B-MCL showed a greater median pixel value with lower variation compared with P-MCL, indicating a homogeneously euchromatin-rich pattern in B-MCL. In addition, the Feret diameter of the nuclei was significantly smaller (median 6.92 vs. 8.49µm per nucleus, P <0.001) and had a lesser degree of variation in B-MCL compared with P-MCL, indicating that B-MCL cells have smaller cells with a more monomorphic appearance. B-MCL showed a significantly higher median Ki-67 proliferation rate (60% vs. 40%, P =0.003), and affected patients had poorer overall survival compared with those with P-MCL (median overall survival: 3.1 vs. 8.8y, respectively, P =0.038). NOTCH1 mutation was significantly more frequent in B-MCL compared with P-MCL (33% and 0%, respectively, P =0.004). Gene expression profiling showed 14 genes overexpressed in B-MCL cases and gene set enrichment assay for the overexpressed genes showed significant enrichment in the cell cycle and mitotic transition pathways. We also report a subset of MCL cases that has blastoid chromatin but a higher degree of pleomorphism in nuclear size and shape, designated here as hybrid MCL. Hybrid MCL cases had a similar Ki-67 proliferation rate, mutation profile, and clinical outcome to B-MCL and distinct from P-MCL. In summary, these data suggest biological differences between B-MCL and P-MCL cases justifying their separate designation when possible.

C14 CASE REPORT: MULTIMODALITY IMAGE–CHALLENGE IN PRIMARY CARDIAC DIFFUSE LARGE B–CELL LYMPHOMA

Abstract A 76–year–old Caucasian woman presented to our hospital with progressive exertional fatigue and weight–loss over 2 months.Her past medical history revealed a recent local–hospital admission because of atrioventricular third–degree block, requiring permanent pacemaker implan­tation. At presentation her cardiovascular exam was normal.Laboratory studies revealed elevated LDH and PCR; electrolytes, cardiac biomarkers and complete blood count were normal. ECG demonstrated AF and ventricular stimulation.Transtoracich echocardiography showed LV hypertrophy in the basal segments, with normal ejection fraction and a reduced LV–GLS with a relative apical sparing pattern.There was a large, well–circumscribed mass arising from the right atrium, with a contextual moderate pericardial effusion (Fig1).Vasculitic, thrombophilic and infectious work–up were negative.The patient was immunocompetent. CMR was proposed but could not be performed due to patient claustrophobia. ECG gated cardiac CT was carried out for a better differential diagnosis of the mass, as well as to look for possible embolization or primary tumours, in the hypothesis of cardiac metastases. A CT total body showed a large ill–defined mass invading the interatrial and interventricular septum with projections into the left ventricle. Not enlarged lymph nodes were detected with neither hepatosplenomegaly nor abdominal lymphadenopathy. A total body 18FDG PET revealed significant tracer uptake in the heart and pericardium without extracardiac uptake, consistent with a malignant cardiac mass (Fig2).LV endomyocardial biopsy was attempted: pathology revealed large B–cell lymphoma expressing CD20, Bcl–2, Bcl–6, Mum–1, C–myc and with a high Ki67 proliferation rate. The patient underwent six cycles of chemotherapy(R–POCH).Echocardiography imaging after the second cycle showed significant reduction in myocardial wall thickness and concomitant improvement in LV–GLS. Repeated PET–CT scans 6 months post–chemotherapy showed complete remission with no evidence of FDG–avid lymphoma (Fig3). Primary cardiac lymphoma (PCL) is an extranodal non–Hodgkin’s B–cell lymphoma exclusively located in the heart or pericardium, accounting for 1–2% of primary cardiac tumours. PCL often presents with non–specific clinical symptoms making the diagnosis challenging. Multimodality approach and myocardial biopsy are essential in the diagnostic work–up. Early diagnosis and treatment are crucial since a good response to chemotherapy is expected.

Abstract P5-09-03: Real World Data on Neoadjuvant Endocrine Treatment and Ki67 Assessment in ER+/HER2- Breast Cancer. Results from a Single-Institution Prospective Cohort Study

Abstract Purpose: Neoadjuvant endocrine treatment (NET) has become a useful tool for the downstaging of luminal-like breast cancers in postmenopausal patients. It enables us to increase breast conserving surgery (BCS) rates and provides an opportunity for assessing in vivo NET effectiveness and studying any biological changes that may act as valid biomarkers. The purpose of this study was to evaluate the effectiveness of NET as well as to assess the role of Ki67 proliferation rate changes as an indicator of endocrine responsiveness. Methods: From June 2016 to January 2022, a single-institution cohort of patients treated with NET and further surgery was evaluated. In patients with Ki67≥10%, a second core biopsy was performed after four weeks. Information regarding histopathological and clinical changes, as well as surgical management, was gathered. Results: A total of 168 estrogen receptor positive (ER+)/HER2 negative patients were included. The median age at diagnosis was 69.5 years old (IQR: 16.0). The median treatment duration was 5.0 months (IQR: 4.0). Median maximum size in the surgical sample was 44.0% smaller than pretreatment size measured by ultrasound (p&amp;lt;.0001), showing an inverse linear relationship with treatment duration. Median pretreatment Ki67 expression was 20.0% (IQR: 18.0) and was reduced to 5.0% (IQR: 8.0) after four weeks, and to 2.0% (IQR: 7.25) in the surgical sample (p&amp;lt; 0.0001). Other significant downgrading changes were observed with respect to tumor grade (p&amp;lt; 0.0001) and progesterone receptor (PR) expression (p&amp;lt; 0.0001). BCS was performed on 145 patients (86.3%). One case of pathological complete response was recorded. A larger Ki67 fold-change after four weeks was significantly related to a PEPI score of 0 (p&amp;lt; 0.002). No differences were observed between luminal A- and B-like tumors with regard to fold-change and PEPI score. No treatment abandonment was produced during the study. Conclusions: In our cohort, NET has proven effective for tumor size and Ki67 downstaging. This results in a higher rate of conservative surgery, aids in therapeutic decision-making, provides prognostic information, and constitutes a safe and well-tolerated approach Biological changes after NET Patient and tumor characteristics Citation Format: Covadonga Marti, Laura Frias, Adolfo Loayza, Elisa Moreno, Marcos Meléndez, Jose Ignacio Sanchez-Mendez. Real World Data on Neoadjuvant Endocrine Treatment and Ki67 Assessment in ER+/HER2- Breast Cancer. Results from a Single-Institution Prospective Cohort Study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-09-03.

Abstract ED3-1: Updates in the pathology of PABC

Abstract Updates in the Pathology of Pregnancy Associated Breast Cancer (PABC) Pregnancy associated breast cancer is defined as a breast cancer diagnosed during gestation, lactation and within 1 to 5 years postpartum. While the development of malignancy during pregnancy is rare, the incidence is increasing; breast cancer is one of the most common cancers diagnosed during pregnancy and the postpartum period occurring in up to 1 in 3000 deliveries. Of interest, breast cancer is the leading cause of cancer death in US women age 15-29. Pregnancy has a dual effect on breast cancer development: on one hand cancer protective and on the other cancer promoting. While a number of hypotheses have been proposed over the years to explain these effects, the most likely hypothesis for the development of PABC is the involution hypothesis. This hypothesis proposes that the involution pathways activated during pregnancy and the immediate postpartum period are remodeling programs similar to wound healing and inflammation that may be associated with tumor development and progression. Although PABCs can be any subtype of breast carcinomas, they are usually invasive ductal carcinomas of high tumor grade and large tumor size with higher stage at presentation and higher rates of lymph node involvement. Most PABCs are hormone receptor negative tumors with high Ki-67 proliferation rates; most frequently, they are either triple negative or HER2-positive carcinomas. A number of studies have shown that PABCs have different genomic signatures than the non-PABC tumors with PABCs having an increased expression of immune response mediators. Better understanding of the molecular pathways of tumor initiation and progression and prompt diagnosis and state-of-art treatment protocols in PABC is expected to lead to better outcomes for these young breast cancer patients. Citation Format: Kalliopi Siziopikou. Updates in the pathology of PABC [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr ED3-1.

Pigmented Inflamed Seborrheic Keratosis of the Bulbar Conjunctiva.

A 57-year-old Black man presented with the recent onset of a pigmented temporal epibulbar lesion. As pigmentation of conjunctival epithelial lesions is correlated with complexion pigmentation, the lesion was presumed to represent a pigmented ocular surface squamous neoplasia (OSSN). Excisional biopsy, however, revealed a pigmented conjunctival seborrheic keratosis, a rare occurrence. The lesion lacked cytologic atypia. Intralesional processes of dendritic melanocytes were demonstrated by hematoxylin-eosin and Melan-A stains. Melanophages also contributed to clinical pigmentation. Subepithelial lymphocytic infiltration, elevated Ki67 proliferative rate, prominent mitotic activity, and subtle spongiosis afforded evidence of inflammation rather than malignancy in a lesion devoid of cytologic atypia.

Primary splenic diffuse large B-cell lymphoma presenting as a splenic abscess.

Diffuse large B-cell lymphoma (DLBCL) arising in the spleen, also known as primary splenic DLBCL (PS-DLBCL), is a rare form of malignant lymphoma. It is defined as a lymphoma confined to the spleen or involving splenic hilar lymph nodes. Here we report a case of PS-DLBCL with CD30. The patient was a 62-year-old who presented with 2 weeks of left flank pain, chills, and abdominal distension. Computed tomography identified an 8-cm splenic mass with central necrosis interpreted as an abscess. A drain was placed, yielding purulent necrotic material; cytologically, only neutrophils were identified. However, purulent drainage continued for 28 days without resolution, prompting splenectomy. Pathological dissection revealed a multinodular mass with central necrosis. Microscopic examination revealed extensive karyorrhexis, abundant ghosts of large cells, and scattered large cells with pleomorphic, multilobated, and vesicular nuclei with moderately abundant cytoplasm. Immunohistochemical staining revealed large, atypical cells positive for CD20, CD30, CD45, PAX5, MYC (>40%), MUM1 (>30%), and p53 (focally). The large cells were negative for CD3 (polyclonal), CD4, CD5, CD8, CD10, CD15, CD34, BCL2, BCL6, AE1/AE3, S100, HHV8, and ALK. The Ki-67 proliferation rate was approximately 80% in large cells. Notably, this PS-DLBCL was positive for CD30, an unusual finding among non-Hodgkin B-cell lymphomas, which, coupled with the Reed-Sternberg-like morphology, raised the possibility of classic Hodgkin lymphoma. Therefore, we reviewed the literature to confirm the unique features of this large B-cell lymphoma, its abscess-like appearance, and its expression of CD30.

Ki-67 Expression, Mast Cells Positive to Tryptase, and Angiogenesis in Gastric Cancer Patients Undergoing Radical Surgery

Objectives: Tumor proliferation is guided by neoangiogenesis; microvascular density (MVD) in the tumor micro-environment increases with the action of different immune system stromal cells such as the mast cells (MCs). Methods: We evaluated Ki-67 proliferation rate, MCs positive to tryptase (MCPT), and MVD in a series of 85 gastric cancer (GC) tissue samples from patients undergoing radical surgery. Results: In tumor tissue, a significant correlation between Ki-67 expression, MCPT, and MVD was found through Pearson t-test analysis (p ranged from 0.01 to 0.03). Conclusion: Ki-67 expression and MVD may indicate the survival prognosis of patients and MCPT could repre-sent a biological marker of radical surgery and angiogenesis. Furthermore, MCPT could be consid-ered as a target of novel anti-angiogenic therapies in GC patients. Keywords: Angiogenesis, gastric cancer, mast cells, surgical oncology, tumor microenvironment, tumor pro-liferation